ROTIFERA. 393 



and the lowest point between every two waves by one 

 folded down completely upon itself, the intervening 

 space being completed by others in every degree of 

 extension, so as to present something of the outline 

 of a cone. As the continuance of each cilium in any 

 one of these positions is of the shortest possible 

 duration, and each takes up in regular succession 

 the action of the adjoining one, that cilium which, 

 by being completely folded up, formed the lowest 

 point between any two waves, in its turn by its 

 complete extension forms the highest point of a 

 wave ; and thus, while the cilia are alternately bend- 

 ing and unbending themselves, each in regular suc- 

 cession after the other, the waves only travel onward, 

 while the cilia never change their position in this 

 direction, having, in fact, no lateral motion."* 



These beautiful but minute creatures are often 

 found in abundance in the leaden shoots of roofs, 

 among the sediment left by rain-water, in the form 

 of dust. If the dried sediment have any particles 

 of a reddish or dark brown colour, it is almost sure 

 to contain them ; and on being steeped awhile in 

 water, these atoms will revive, and display the forms 

 and motions described above. 



* Philosophical Transactions, 1837. 



s 5 



